what is the difference between linux and unix?

The difference between Linux and Unix Some PC-Unix and Linux in the realization similar. Almost all commercial Unix versions of the basic support of the same software, programming environment and network characteristics. However, Linux and Unix versions are still in business there are many differences. Linux supports hardware and commercial Unix are different. In general, commercial Unix support for more hardware, but the Linux support of hardware is also expanding. Notably, Linux and commercial Unix at least as stable. For many users, the most important factor is price. Linux is free software, users can download from the Internet. If the Internet inconvenient, you can get it cheaper through mail-order Linux-disk or CD-ROM. Of course, you can get directly from a friend. The value of commercial Unix should not be to belittle. In addition to the price of the software itself, users need to pay for documentation, after-sales support and warranty costs. For larger institutions, these are very important, but not from PC, the user may do any good. Many commercial companies and universities, and other units have been found in the laboratory using low-cost PC machines running Linux than with commercial Unix workstations running okay. Linux can be provided on PC-workstation features, while the PC-workstations at a fraction of the price. There are also cheaper for the PC machine Unix, one of the most famous is the 386BSD. In many ways, 386BSD packages and Linux-compatible, but Linux is more suited to the needs of users. The most significant is that, Linux's development is open to any volunteer can contribute to the development process. In contrast, 386BSD was developed by a closed team. By doing so, these two products there is a serious conceptual and design differences: Linux's goal is to start from scratch to develop a complete Unix system; 386BSD's goal is to modify the existing BSD do to fit 80386 system

In terms of commands they are the same because linux is an alternative for Unix and very compatible with each other in terms of software used. I think Unix are commercially available whereas Linux is free to use. Mostly Linux right now are mostly on every servers in the world and also they are penetrating the desktop market to compete with Microsoft.